Interfacing with a Macintosh Classic II

Hi guys,

A very geeky gift has been bestowed on me in the form of a working Macintosh Classic II.

With no networking capabilities, I'm trying to think of something useful to do with this machine. I note two "RS-422 Serial Ports" are on the back of the unit, and wonder whether it is possible to get the Arduino communicating with it.

Anyone know if this is possible? Even just being able to get some kind of serial monitor viewable on the machine would be great, but I guess I may be limited by the software I can find for it. for more information.

Thanks all.

You can certainly use the Mac Classic II as a terminal to monitor serial data from a serial device such as the Arduino. You’ll need a TTL-to-RS422 buffer chip, of course. If the machine has an old version of MacOS on it (probably about MacOS version 7), there may be a terminal emulator program already installed.

The really challenging thing would be to run the Arduino IDE on it! It’s in Java, so if you can find a Java system for the old MacOS, then you have at least a chance of making it work.

THanks for the confirmation. Do you have any links / further reading suggestions?

I'm not greatly familiar with System 7, and have thusfar found nothing that resembles a terminal emulator installed. The machine looks to have a clean 7.5 OS, and I have the original 7.01 installer disks with tidbits. None of them have seemed helpful.

I used to use Kermit as a terminal emulator on the old system 7. Try looking for a version of that. The trouble is that a lot of that stuff is pre internet. I wrote a PCB layout package for that machine that emulated pads and tracks and I also wrote a serial monitor which would send out a byte displayed in bits and display the returned byte in bits. This went with some hardware I built that sent data to a UART and outputted the bits then sent the received bits back. You need some sort of language to run on it. I used to use Forth and ThinkC. It's a lot easer now. :)

You may have ZTerm installed already:

It was a popular terminal emulator in the Mac System 7 days. Or, you could install an old version that's compatible with Mac System 7, if you can arrange the file transfer/unpacking.

You'll need a TTL-to-RS422 buffer chip, of course.

Why do you need this? I've owned an Atari Falcon for 15 years now, and back in the old days when we were still using modems, I had a modem connected to the Falcon's RS422-port using a simple 422->232 cable originally made for classic Macs. I would assume that the same will work on a Mac.

TTL-to-RS422 buffer chip, of course.

No you don't the RS422 is a differential driver, you just need to use one side of this for the transmit (-ve) and one side for the receive (-ve) and ground the other side of the receive (+ve).

Hmmm... Yes, I think that's right. Isn't RS-422 a 5V differential signalling system? So you could just connect a TTL async serial line to it, but you'd have to be careful to get the inverted/not inverted polarity right.